JPS6020959B2 - stereo signal processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stereo signal processing unit, and more particularly to a stereo signal processing device that appropriately performs phase processing on left and right channel signals of a stereo device and reproduces the same.

Conventional stereo playback devices have only been required to have high fidelity playback, but recently, for example, reverberation components are added to the playback sound (or signal), or the sound image localization of the left and right channels is changed, etc. Regeneration methods that pursue richness as places are beginning to attract attention.

As a method of varying the sound image localization mentioned above, there is a method of creating a difference between the amplitudes of the left and right channel signals, but with this method it is difficult to obtain a sense of expansion of the sound field, and it is difficult to create a sufficient sound field. There is a drawback that abundance is not bound. An object of the present invention is to provide a stereo signal processing device that can provide a sound field with a sufficient sense of expansion and can be used as a sound field where dynamic sounds can be enjoyed.

In the stereo signal processing device of the present invention, the phase of the first channel signal is shifted by a certain amount (including zero) by the first phase shifter, and the phase of the second channel signal can be controlled by the amount of phase shift. The phase is shifted by a second phase shifter, and the phase is shifted such that the phase shift amount of the first phase shifter is included between the maximum and minimum phase shift amount of the second phase shifter. 2nd using quantity controller
control the phase shifters of these first and second phase shifters over time.
The outputs of the phase shifters are input to each speaker via, for example, an intensifier. With this configuration, the phase difference between the radiated sound from the first and second speakers (left and right speakers) changes over time, and the sound image is localized at the center at the moment when the left and right speakers are in the same phase, and at each other moment. You will feel the sound image localization on the phase-advanced channel side,
As a result, the localization of the sound image moves left and right, making it possible to give a sense of expansion of the sound field, giving a dynamic feeling to stereo playback, and thus providing a richer sound field.

Hereinafter, the present invention will be explained in detail using the accompanying drawings. 1st
The figure is a schematic block diagram showing an embodiment of the present invention. In the figure, a left channel signal of a stereo signal, for example, is input to a phase shifter 2 from an input terminal 1, and its phase is fixed by a constant phase shift amount 8c ( ).

The output signal of the phase shifter 2 is input to the left channel speaker 4 via the amplifier 3 and outputted as an acoustic signal. On the other hand, the right channel signal is input to the phase shifter 6 from the input terminal 5.

This phase shifter 6 has a configuration in which the amount of phase shift is variably controlled by a control signal, and in order to generate the control signal, an external phase shift modulation input signal is applied via an input terminal 7 to control the amount of phase shift. A phase shifter 8 is used, the output signal of which is applied as the aforementioned control signal to the control input of the phase shifter 6. Therefore, the right channel input signal having a predetermined phase is outputted with its phase changed by the phase shifter 6 according to the control signal, and the sound is outputted through the amplifier 9 and the right channel speaker 10 similarly to the left channel. will be done. Figure 2a is a preferred example showing the relationship between the phase shift amounts of phase shifters 2 and 6. In the figure, the axis represents time t (seconds), and the vertical axis represents the phase shift amount 0 of each phase shifter. It shows.

First, the phase shifter 2 for the left channel signal has a constant phase shifter oc regardless of the time t, as described above. On the other hand, the phase shifter 6 for the right channel signal changes drawing a sine (or cosine) wave-like curve with the passage of time t within the range of ±Q with the phase shift amount 8c of the previous phase shifter 2 as the center. The phase shift amount is as follows. Therefore, the minimum phase shift amount of phase shifter 6 is 8L.
=8. -Q to maximum OH=ac+Q. For this purpose, a phase shift amount controller 8 is used, and if the characteristics of this controller 8 are set so that the amount of phase shift of the phase shifter 6 is proportional to the phase modulation input signal, By changing the phase modulation input signal in a sine (or cosine) wave manner, it is possible to obtain a sine wave shape as shown in FIG. 2a.

Therefore, after the left and right channel signals pass through the phase shifters 2 and 6, the phase difference △ between the two signals becomes a sine (or cosine) wave-like curve as shown in Figure 2b, and the phase difference between the acoustic outputs from the speakers is Similarly, it will change in a sinusoidal manner.

In this case, when two sound sources emitting the same vibration and frequency are placed at an appropriate interval, the human auditory sense localizes the sound source to the one whose phase is leading due to the binaural effect. It has the property of feeling.

Furthermore, in a general stereo program source, both channels contain a component with the same content, and in a normal reproduction method, this component is a sound image localized at the center of the left and right speakers. Taking this fact into account, looking at the phase relationship between the left and right channel sounds in FIG.

Also, from time t, to t2, the left channel is in phase, and is in phase at a time ratio of 2, so the time ratio,
At the in-phase moments such as and t2, the sound image is localized to the center, and until time t2, the sound image is localized to the right channel side with respect to the center localized component in the program source, and on the other hand, at time t, It can be seen that from t2 to t2, the image is localized to the left channel side. The movement of the localization of the sound image at this time is shown by the dotted line in FIG. 3, and the dashed-dotted line shows the elapse of time t. In this case, the phase difference between both channels has a maximum value Q of 4? As shown by the dotted line in Figure 3, the sound image will be completely localized to one sound source at the moment when the phase difference is maximum. The sound changes sinusoidally between the two sound sources, centering on the direct line, and provides a sufficient sense of sound expansion. It is not necessary to change the phase difference in the form of a sine (or cosine) wave; it is possible to change the phase difference in an arbitrary waveform to obtain a variety of sound spread sensations, and the phase shifter 6
It is not necessary that the phase shift amount of the phase shifter 2 is varied around the phase shift amount of the phase shifter 2, and the point is that the latter phase shift amount only needs to be included in the range of the maximum and minimum value of the former phase shift amount. . As detailed above,
According to the present invention, it is possible to obtain a sufficient sense of spaciousness of the sound image, which could not be obtained with the conventional variable localization method, which creates a difference in the amplitude of the left and right channel signals. This has the advantage of providing a rich sound field.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. FIG. 3, a diagram showing the relationship between phase difference and time, is a schematic diagram illustrating the sound image localization state of the speaker radiated sound according to the present invention as a function of time. Explanation of symbols of main parts: 1... Left channel signal input terminal, 2, 6... Phase shifter, 3, 9...
・Intensifier, 4, 10...Speaker, 5...Right channel signal input terminal, 8...Phase shift amount controller. Traditional/Pictures 2 to) Traditional 3

Claims (1)

[Claims] 1. A first phase shifter that shifts the phase of one of the left and right stereo channel signals by a predetermined amount, and a second phase shifter whose phase shift amount is controllable and that shifts the other phase of the left and right stereo channel signals. and a phase shift amount controller that controls the phase shift amount of the second phase shifter to change in a cosine or sine wave shape over time with the phase shift amount of the first phase shifter as the center. and first and second speakers driven in accordance with the outputs of the first and second phase shifters, respectively.